A novel durable flame retardant for cotton fabrics based on diethylenetriamine

A novel flame retardant, diethylenetriamine pentamethyl triphosphonate methyl ester ammonium diphosphonate flame retardant (DETA-P), was synthesized and characterized by NMR and FTIR. DETA-P-treated cotton fabrics showed excellent flame retardancy and durability. The limiting oxygen index (LOI) of cotton fabrics treated with 30 wt% DETA-P reached 40.7% and after 50 laundering cycles (LCs), according to the AATCC 61-2013 2A standard, still reached 29.0%. The energy dispersive X-ray (EDX) results of showed that there were P and N elements in CF-3. After 50 LCs, the total metal ion content of DETA-P treated cotton was noticeably lower than that of ammonium salt of diethylene triamine penta methylene phosphonic acid (ADTPMPA)-treated cotton. The scanning electron microscopy (SEM) and EDX results suggested that DETA-P molecules entered the cotton fiber interior. The results of the Fourier transform infrared (FTIR) and durability analyses showed that DETA-P grafted the -OH of cellulose molecules through P-O-C in cotton fibers. Thermogravimetry (TG) results showed that DETA-P changed the thermal decomposition pathway of cotton fibers. The cone calorimetry results indicated that the heat release rate and total heat release of DETA-P-treated cotton were much lower than for untreated cotton. These results showed that the introduction of phosphonate groups and reactive ammonium phosphorus acid groups into a flame retardant molecule was an effective method to improve the flame retardancy and durability of the cotton fibers. (C) 2021 Published by Elsevier Ltd.